<!DOCTYPE html>
<html lang="en" xmlns="http://www.w3.org/1999/xhtml" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="utf-8">
    <title>Thymeleaf</title>
</head>
<body>
<!--th:if属性， 条件判断-->
<h1>th:if属性--------<span th:if="${if_msg} == 'R'" th:text="${if_msg}"></span></h1>
<h1>th:if属性--------<span th:if="${if_msg} == 'L'" th:text="${if_msg}"></span></h1>

<!--th:unless属性：条件结果取反操作-->
<h1>th:if属性--------<span th:unless="${if_msg} == 'L'" th:text="${if_msg}"></span></h1>

<!--th:switch属性-->
<div th:switch="${if_msg}">
    <p th:case="R">是R</p>
    <p th:case="L">是L</p>
    <p th:case="T">是T</p>
    <p th:case="B">是B</p>
</div>
</body>
</html>